<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>border-color效果</title>
  <style type="text/css">
    body {
      color: #fff;
      background: #222;
    }

    h1 {
      font-size: 14px;
      font-family: "Microsoft Yahei";
      text-align: center;
    }

    .butterfly,
    .butterfly .circle {
      display: block;
      width: 300px;
      height: 300px;
      border-radius: 50%;
    }

    .butterfly {
      position: relative;
      margin: 50px auto;
    }

    .butterfly .circle {
      position: absolute;
      top: 0;
      left: 0;
      border: 1em solid #3b8210;
      z-index: -1;
      border-bottom-color: #ebc90b;
      border-right-color: #ebc90b;
      -webkit-transition: -webkit-transform 1s linear;
      transition: transform 1s linear;
    }

    .butterfly img {
      width: 100%;
      height: auto;
    }

    .butterfly:hover .circle {
      -webkit-transform: rotate(180deg);
      transform: rotate(180deg);
    }
  </style>
</head>
<body>
<h1>请使用webkit内核标准浏览器查看效果</h1>
<a href="http://image.haosou.com/i?q=%E8%9D%B4%E8%9D%B6&src=tab_www" class="butterfly" target="_blank">
  <div class="circle"></div>
  <img src="http://p3.qhimg.com/t014ca5b3e65fe126a6.png" alt=""/>
</a>
</body>
</html>
